Exhaust heat recovery device

ABSTRACT

An exhaust heat recovery device able to secure heat exchange performance even when tilted, provided with an evaporator exchanging heat between an exhaust gas and an evaporable and condensable working fluid sealed inside it and thereby evaporating the working fluid and a condenser exchanging heat between the working fluid evaporated by the evaporator and the cooling water and thereby condensing the working fluid, wherein the evaporator and condenser are arranged in a closed loop channel through which the working fluid circulates, the evaporator and condenser are arranged adjoining each other in the substantially horizontal direction, the evaporator is provided with a plurality of evaporation side heat pipes arranged in parallel and is provided with a first evaporation side header communicating one ends of the plurality of evaporation side heat pipe and a second evaporation side header communicating the other ends, and, when mounted in a vehicle in a horizontal state, the second evaporation side header arranged at the bottom among the two evaporation side headers is arranged with the side far from the condenser positioned lower than the side close to it.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exhaust heat recovery device usedfor an automobile or other vehicle.

2. Background Art

In recent years, there has been known the art of utilizing the principleof a heat pipe to recover the exhaust heat of the exhaust gas from theexhaust system of an engine of a vehicle and utilize this exhaust heatfor assisting warmup etc.

This exhaust heat recovery device arranges an evaporator of the heatpipe in an exhaust pipe of the engine, arranges a condenser of the heatpipe in the cooling water passage of the engine, and uses the exhaustheat of the exhaust gas to heat the cooling water (for example, seeJapanese Patent Publication (A) No. 62-268722).

Further, as a heat exchanger utilizing the principle of a heat pipe, aloop type heat pipe heat exchanger has been proposed (for example, seeJapanese Patent Publication (A) No. 4-45393). This has a sealedcirculating passage forming a closed loop, an evaporable and condensableheat transfer fluid sealed in the circulating passage, an evaporatorarranged in the circulating passage and evaporating the working fluid byheat input from the outside, and a condenser arranged at a positionhigher than the evaporator of the circulating passage and exchangingheat between the heat transfer fluid evaporated by the evaporator andthe fluid transferred heat to from the outside.

Summarizing the problems to be solved by the invention, when providingan exhaust heat recovery device of a simple, compact structureadvantageous for mounting in a vehicle, it is preferable to make theevaporator and condenser integral. Giving one example, a configurationsuch as shown in FIG. 7 where the evaporator J1 and condenser J2 arearranged adjoining each other in the horizontal direction and the twoends in the vertical directions of the heat pipes J3 of the evaporatorJ1 and condenser J2 are communicated by headers (communicating parts) J5may be considered.

In the exhaust heat recovery device, the working fluid evaporated at theevaporator J1 flows through the upper header J5 into the condenser J2.The condenser J2 condenses the working fluid, which becomes a liquidwhich then flows through the lower header J5 into the evaporator J1. Dueto the balance between the evaporation of the working fluid in such anevaporator J1 and the condensation of the working fluid in the condenserJ2, a difference in level of the working fluid (liquid) (water headdifference h₁) arises between the evaporator J1 and condenser J2. Due tothis water head difference h1, the working fluid is refluxed from thecondenser J2 to the evaporator J1. Due to this, the working fluid iscirculated.

When the vehicle is tilted and, as shown in FIG. 8, the exhaust heatrecovery device is tilted in the horizontal direction so that theevaporator J1 becomes higher in the vertical direction than thecondenser J2, the water head difference h₂ between the evaporator J1 andcondenser J2 becomes smaller. For this reason, there is the problem thata sufficient amount of working fluid can no longer be refluxed from thecondenser J2 to the evaporator J1 and the heat exchange performanceremarkably falls.

However, an exhaust heat recovery device can improve the fuel economyand heating performance since it is possible to raise the temperature ofthe cooling water early by recovery of the exhaust heat at the time ofstartup in the winter. On the other hand, to avoid overheating at thetime of high engine load in the summer, it is possible to stop therecovery of the exhaust heat. For this reason, as shown in FIG. 9, theexhaust heat recovery device is preferably provided with a valvemechanism J6 for stopping the circulation of the working fluid. Notethat FIG. 9 shows a state where the exhaust heat recovery device istilted with respect to the horizontal direction so that the evaporatorJ1 becomes higher than the condenser J2.

The exhaust heat recovery device shown in FIG. 9 is provided with anevaporation side connecting part J71 guiding working fluid evaporated bythe evaporator J1 to the condenser J2 and a condensation side connectingpart J72 guiding working fluid condensed at the condenser J2 to theevaporator J1. Further, the end of the condensation side connecting partJ72 at the evaporator J1 side is connected to the heat pipe J3 arrangedat the side of the evaporator J1 closest to the condenser J2.

In an exhaust heat recovery device provided with such a valve mechanismJ6, pressure loss occurs in the valve mechanism J6, so when the exhaustheat recovery device is tilted so that the evaporator J1 becomes higherthan the condenser J2, it becomes hard for the working fluid to berefluxed from the condenser 2 to the evaporator 1 and the working fluidends up remaining in the condensation side connecting part J72. Ifplaced under a low temperature environment in this state, there is theproblem that the working fluid remaining in the condensation sideconnecting part J72 will freeze and the condensation side connectingpart J72 will end up being blocked. Further, along with the workingfluid remaining in the condensation side connecting part J72 freezing,there is the problem that the internal pressure occurring due to theexpansion in volume ends up exceeding the pressure resistant strength ofthe condensation side connecting part J72 and breaking it.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an exhaust heatrecovery device able to secure a heat exchange performance even whentilted.

Another object is to provide an exhaust heat recovery device able toprevent blockage or breakage of a condensation side connecting part whentilted.

To achieve the above objects, the present invention provides an exhaustheat recovery device carried in a vehicle using an internal combustionengine as a drive source for operation and provided with an evaporator(1) arranged in an exhaust gas passage through which exhaust gasexhausted from the internal combustion engine runs, exchanging heatbetween the exhaust gas and an evaporable and condensable working fluidsealed inside it, and thereby evaporating the working fluid and acondenser (2) arranged in the cooling water passage through whichcooling water of the internal combustion engine runs, exchanging heatbetween the working fluid evaporated by the evaporator (1) and coolingwater, and thereby condensing the working fluid, wherein the evaporator(1) and condenser (2) are arranged in a closed loop channel throughwhich the working fluid circulates, the evaporator (1) and condenser (2)are arranged to adjoin each other in the substantially horizontaldirection, the evaporator (1) has a plurality of evaporation side heatpipes (3 a) arranged in parallel and is provided with a firstcommunicating part (51 a) communicating with first ends of the pluralityof evaporation side heat pipes (3 a) and a second communicating part (52a) communicating with the other ends, and, when mounted in a vehicle inthe horizontal state, the second communicating part (52 a) arranged atthe bottom among the two communicating parts (51 a, 52 a) is positionedwith the side far from the condenser (2) lower than the side near it.

In this way, by positioning the second communicating part (52 a)arranged at the bottom among the two communicating parts (51 a, 52 a) inadvance with the side far from the condenser (2) lower than the closeside, when the exhaust heat recovery device as a whole is tilted so thatthe evaporator (1) becomes above the condenser (2), the water headdifference between the evaporator (1) and condenser (2) can be kept frombecoming small. Due to this, even when tilted, a sufficient amount ofworking fluid can be refluxed from the condenser (2) to the evaporator(1), so the heat exchange performance can be secured.

Further, in the present invention, there is provided an exhaust heatrecovery device carried in a vehicle using an internal combustion engineas a drive source for operation and provided with an evaporator (1)arranged in an exhaust gas passage through which exhaust gas exhaustedfrom the internal combustion engine runs, exchanging heat between theexhaust gas and an evaporable and condensable working fluid sealedinside it, and thereby evaporating the working fluid, a condenser (2)arranged in the cooling water passage through which cooling water of theinternal combustion engine runs, exchanging heat between the workingfluid evaporated by the evaporator (1) and cooling water, and therebycondensing the working fluid, an evaporation side connecting part (71)guiding the working fluid evaporated at the evaporator (1) to thecondenser (2), and a condensation side connecting part (72) guiding theworking fluid condensed at the condenser (2) to the evaporator (1), whenmounted in a vehicle in the horizontal state, the condensation sideconnecting part (72) being positioned with the side far from thecondenser (2) below the side close to the condenser (2).

According to this, when the exhaust heat recovery device as a whole istilted so that the evaporator (1) becomes higher than the condenser (2),the water head difference of the evaporator (1) and condenser (2) can bekept from becoming small. Due to this, even when tilted, a sufficientamount of working fluid can be refluxed from the condenser (2) to theevaporator (1), so the heat exchange performance can be secured.

Further, when the exhaust heat recovery device as a whole is tilted sothat the evaporator (1) becomes higher than the condenser (2), it ispossible to prevent working fluid from ending up remaining in thecondensation side connecting part (72). For this reason, it is possibleto prevent blockage or breakage of the condensation side connecting part(72) under a low temperature environment.

Further, in the above exhaust heat recovery devices,

the bottom ends of the evaporation side heat pipes (3 a) at the side farfrom the condenser (2) among the plurality of evaporation side heatpipes (3 a) may be positioned lower than the bottom ends of theevaporation side heat pipes (3 a) at the close side.

Further, the above exhaust heat recovery devices may be further providedwith a valve mechanism (6) provided at a downstream side in thecondenser (2) and switching the channel through which the condensedworking fluid flows into the evaporator (1).

In this case, a pressure loss occurs in the valve mechanism (6), so whenthe exhaust heat recovery device is tilted so that the evaporator (1)becomes higher than the condenser (2), it becomes hard for the workingfluid to be refluxed from the condenser (2) to the evaporator (1).Therefore, when providing the valve mechanism (6), the features can besaid to be more effective.

Note that the reference numerals in parentheses after the above meansshow the correspondence with specific means described in the laterexplained embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome clearer from the following description of the preferredembodiments given with reference to the attached drawings, wherein:

FIG. 1 is a cross-sectional view showing an exhaust heat recovery deviceaccording to a first embodiment;

FIG. 2 is a cross-sectional view showing an exhaust heat recovery deviceaccording to a second embodiment;

FIG. 3 is a cross-sectional view showing an exhaust heat recovery deviceaccording to a third embodiment;

FIG. 4 is an enlarged cross-sectional view of a part A of FIG. 3;

FIG. 5 is a cross-sectional view showing an exhaust heat recovery deviceaccording to a fourth embodiment;

FIG. 6 is a cross-sectional view showing an exhaust heat recovery deviceaccording to a fifth embodiment;

FIG. 7 is a cross-sectional view showing a conventional exhaust heatrecovery device;

FIG. 8 is a cross-sectional view showing the state of a conventionalexhaust heat recovery device tilted with respect to the horizontaldirection; and

FIG. 9 is a cross-sectional view showing the state of an exhaust heatrecovery device having a conventional valve mechanism J6 tilted withrespect to the horizontal direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Below, a first embodiment of the present invention will be explainedbased on FIG. 1. The exhaust heat recovery device of the presentembodiment recovers the exhaust heat of the exhaust gas from the exhaustsystem of the engine of a vehicle (internal combustion engine) andutilizes this exhaust heat for assisting warmup.

FIG. 1 is a cross-sectional view showing an exhaust heat recovery deviceaccording to the first embodiment. As shown in FIG. 1, the exhaust heatrecovery device of the present embodiment is provided with an evaporator1 and condenser 2.

The evaporator 1 is provided inside a first housing 100 arranged in anexhaust pipe of a not shown engine. Further, the evaporator 1 performsheat exchange between the exhaust gas and the later explained workingfluid and evaporates the working fluid.

The condenser 2 is provided outside the exhaust pipe and is providedinside a second housing 200 arranged in the cooling water passage of anot shown engine. Further, the condenser 2 exchanges heat between theworking fluid evaporated by the evaporator 1 and the engine coolingwater to condense the working fluid. The second housing 200 is providedwith a cooling water inflow port 201 connected to the cooling wateroutlet side of the engine and a cooling water outflow port 202 connectedto the cooling water inlet side of the engine.

The evaporator 1 and condenser 2 are arranged adjoining each other inthe horizontal direction. Normally, an exhaust pipe (not shown) isprovided across the front-rear direction of the vehicle, so thedirections of arrangement of the evaporator 1 and condenser 2 match inthe vehicle width direction.

Next, the configuration of the evaporator 1 will be explained.

The evaporator 1 has a plurality of evaporation side heat pipes 3 a andcorrugated fins 4 a bonded to the outer surfaces of the evaporation sideheat pipes 3 a. The evaporation side heat pipes 3 a are formed flattenedso that the direction of circulation of the exhaust gas (directionvertical to paper surface) matches with the long diameter direction andare arranged in parallel so that their longitudinal directions matchwith the vertical direction.

In the evaporator 1, at the two ends of the evaporation side heat pipes3 a in the longitudinal direction, evaporation side headers 5 aextending in the stacking direction of the evaporation side heat pipes 3a and communicating with all evaporation side heat pipes 3 a areprovided. The evaporation side header 5 a arranged at the top end of theexhaust heat recovery device among the evaporation side headers 5 a willbe referred to as the “first evaporation side header 51 a”, while theevaporation side header 5 a arranged at the bottom will be referred toas the “second evaporation side header 52 a”. Note that firstevaporation side header 51 a corresponds to the first communicating partof the present invention, while the second evaporation side header 52 acorresponds to the second communicating part.

Next, the configuration of the condenser 2 will be explained.

The condenser 2 has a plurality of condensation side heat pipes 3 b. Thecondensation side heat pipes 3 b are formed flattened so that thedirection of circulation of the engine cooling water (direction verticalto paper surface) matches with the long diameter direction and arearranged in parallel so that their longitudinal directions match withthe vertical direction.

In the condenser 2, at the two ends of the condensation side heat pipes3 b in the longitudinal direction, condensation side headers 5 bextending in the stacking direction of the condensation side heat pipes3 b and communicating with all condensation side heat pipes 3 b areprovided. Among the condensation side headers 5 b, the condensation sideheader 5 b arranged at the top end side of the exhaust heat recoverydevice in the vertical direction will be called the “first condensationside header 51 b”, while the condensation side header 5 b arranged atthe bottom end side in the vertical direction will be called the “secondcondensation side header 52 b”.

The evaporation side headers 5 a and the condensation side headers 5 bare connected in a communicable state. Further, the evaporation side andcondensation side heat pipes 3 a, 3 b and evaporation side condensationside headers 5 a, 5 b form a closed loop. Water, alcohol, or anotherevaporable and condensable working fluid is sealed inside these.

Further, the second condensation side header 52 b has a valve mechanism6 provided inside it. The valve mechanism 6 forms a diaphragm typeswitching means for forming a channel connecting the condensation sideheat pipes 3 b and second evaporation side header 52 a and switchingchannels in accordance with the internal pressure of the evaporationside heat pipes 3 a (pressure of working fluid). Specifically, the valvemechanism 6 is configured to close from the usual open state when theinternal pressure rises and exceeds a first predetermined pressure at apredetermined cooling water temperature and conversely to open againwhen the internal pressure falls and becomes less than a secondpredetermined pressure lower than the first predetermined pressure.

In the present embodiment, the second evaporation side header 52 a isarranged tilted with respect to the horizontal direction so that aportion at a side far from the condenser 2 becomes lower than theportion at the side close to the condenser 2 when the vehicle in whichthe exhaust heat recovery device is carried is positioned on ahorizontal road surface. The bottom ends of the evaporation side heatpipes 3 a at the side far from the condenser 2 are positioned lower thanthe bottom ends of the evaporation side heat pipes 3 a at the side closeto the condenser 2. In the present embodiment, the tilt angle θ of thesecond evaporation side header 52 a with respect to the horizontaldirection becomes 3° to 20° in range. Further, the first evaporationside header 51 a is arranged so as not to be tilted, that is, with alongitudinal direction (stacking direction of evaporation side heatpipes 3 a) matching with the horizontal direction.

As explained above, by arranging the second evaporation side header 52 atilted in advance so that the portion at the side far from the condenser2 becomes lower than the portion at the side close to the condenser 2,it is possible to suppress the reduction of the water head differencebetween the evaporator 1 and condenser 2 when the evaporator 1 is tiltedso as to become higher than the condenser 2. Due to this, even whentilted, a sufficient amount of working fluid can be refluxed from thecondenser 2 to the evaporator 1, so the heat exchange performance can besecured.

Further, in the present embodiment, the second condensation side header52 b is provided inside it with a valve mechanism 6 for controlling theflow of the working fluid from the condenser 2 to the evaporator 1. Inthis case, pressure loss occurs in the valve mechanism 6, so when theexhaust heat recovery device is tilted so that the evaporator 1 becomeshigher than the condenser 2, it becomes hard for the working fluid to berefluxed well from the condenser 2 to the evaporator 1. Therefore, whenproviding the valve mechanism 6, such a configuration (secondevaporation side header 52 a arranged tilted so that the part at theside far from the condenser 2 becomes lower than the part at the sideclose to the condenser 2) can be said to be more effective.

Note that the usually envisioned tilt angle of a road surface in thevehicle width direction is not more than 20°. For this reason, by makingthe tilt angle θ of the second evaporation side header 52 a with respectto the horizontal direction 3° to 20° in range, it is possible to handlethe usually envisioned range of tilt of a road surface.

Second Embodiment

Next, a second embodiment of the present invention will be explainedbased on FIG. 2. Parts similar to those in the first embodiment areassigned the same reference numerals and explanations will be omitted.

FIG. 2 is a cross-sectional view showing an exhaust heat recovery deviceaccording to the second embodiment. As shown in FIG. 2, the evaporationside headers 5 a and the condensation side headers 5 b are connected ina communicable state through tubular connecting parts 7. Further, theevaporation side and condensation side heat pipes 3 a, 3 b, evaporationside and condensation side headers 5 a, 5 b, and connecting parts 7 forma closed loop. Water, alcohol, or another evaporable and condensableworking fluid is sealed inside these.

Further, the evaporator 1 is arranged tilted with respect to thehorizontal direction so that the part at the side far from the condenser2 becomes lower than the part at the side close to the condenser 2 whenthe exhaust heat recovery device is carried in a vehicle in thehorizontal state. At that time, in the evaporation side headers 5 a, theends at the sides far from the condenser 2 become lower than the ends atthe sides close to the condenser 2. That is, the bottom ends of theevaporation side heat pipes 3 a at the side far from the condenser 2 arepositioned below the bottom ends of the evaporation side heat pipes 3 aat the side close to the condenser 2. Note that in the presentembodiment, the first housing 100 is arranged tilted by a tilt angle θsimilar to the evaporator 1.

The end of the bottom surface 110 (lower surface) of the first housing100 at the side far from the condenser 2 is formed with a condensedwater catch 111 able to store the exhaust condensed water. Note that the“exhaust condensed water” means the water generated due to condensationof the moisture contained in the exhaust gas due to the exhaust gasbeing rapidly cooled in the evaporator 1 right after engine startup whenthe temperature of the evaporator 1 is low. The first housing 100 istilted with respect to the horizontal direction so that the side farfrom the condenser 2 becomes lower, so the exhaust condensed water flowstoward the condensed water catch 111. Due to this, the exhaust condensedwater can be stored in one location, so discharge of the exhaustcondensed water becomes easy.

As explained above, when arranging the second evaporation side header 52a tilted in advance so that the portion of the side far from thecondenser 2 becomes lower than the portion at the side close to thecondenser 2 to thereby make the evaporator 1 become higher than thecondenser 2, the water head difference between the evaporator 1 andcondenser 2 can be kept from becoming smaller. Due to this, effectssimilar to those of the first embodiment can be obtained.

Third Embodiment

Next, a third embodiment of the present invention will be explainedbased on FIG. 3 and FIG. 4. Parts similar to those in the firstembodiment are assigned the same reference numerals and explanationswill be omitted.

FIG. 3 is a cross-sectional view showing an exhaust heat recovery deviceaccording to the third embodiment, while FIG. 4 is an enlargedcross-sectional view of a part A of FIG. 3. As shown in FIG. 3 and FIG.4, the evaporation side heat pipes 3 a of the present embodiment areformed by pairs of shaped plates 31, 32 mating in cross-section alongthe longitudinal direction. The pairs of shaped plates 31, 32 are formedinto dish shapes (cross-sectional U-shapes).

The two end sides of the pairs of shaped plates 31, 32 in thelongitudinal direction are formed with pairs of tubular flange parts 33projecting out in the opposite directions toward the outsides of theevaporation side heat pipes 3 a. One flange part 33 of each pair offlange parts 33 has a larger open size than the other flange part 33.For this reason, the end of one flange part 33 fits into the end ofanother flange part 33 for engagement.

The evaporation side headers 5 a are formed by stacking the flange parts33 of the evaporation side heat pipes 3 a and the longitudinal directionends of the evaporation side heat pipes 3 a and are communicated witheach other by the engagement of the ends of the adjoining flange parts33.

In the present embodiment, the adjoining evaporation side heat pipes 3 aare arranged offset from each other in the vertical direction. Morespecifically, in adjoining evaporation side heat pipes 3 a, theevaporation side heat pipe 3 a at the side far from the condenser 2 ispositioned lower than the evaporation side heat pipe 3 a at the sideclose to the condenser 2.

At that time, the channels formed by adjoining pairs of flange parts 33in the evaporation side headers 5 a (hereinafter referred to as the“header component members 34”) are arranged in steps. More specifically,in the adjoining header component members 34, the header componentmember 34 at the side far from the condenser 2 is arranged so as to belower than the header component member 34 at the side close to thecondenser 2. Therefore, the evaporation side headers 5 a are arranged sothat the end in the vehicle width direction at the side far from thecondenser 2 becomes lower than the end of the side close to thecondenser 2.

Due to this, effects similar to those of the first embodiment can beobtained.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be explainedbased on FIG. 5. Parts similar to those in the third embodiment areassigned the same reference numerals and explanations will be omitted.

FIG. 5 is a cross-sectional view showing an exhaust heat recovery deviceaccording to the fourth embodiment. As shown in FIG. 5, the firstevaporation side headers 51 a of the present embodiment are arranged inparallel in the horizontal direction. More specifically, the firstevaporation side headers 51 a are arranged so that their longitudinaldirections (stacking directions of evaporation side heat pipes 3 a)match in the horizontal direction. At that time, in the plurality ofevaporation side heat pipes 3 a, the closer to the condenser 2, thelonger the length in the longitudinal direction.

Due to this, effects similar to those of the third embodiment can beobtained.

Fifth Embodiment

Next, a fifth embodiment of the present invention will be explainedbased on FIG. 6. Parts similar to those in the first embodiment areassigned the same reference numerals and explanations will be omitted.

FIG. 6 is a cross-sectional view showing an exhaust heat recovery deviceaccording to the fifth embodiment. As shown in FIG. 6, in the presentembodiment, second evaporation side headers 51 a, 52 a are arranged inparallel in the horizontal direction. Further, corrugated fins 4 b arebonded to the outer surfaces of the condensation side heat pipes 3 b.

Further, the evaporation side headers 5 a and the condensation sideheaders 5 b are connected in a communicating state through tubularconnecting parts 7. Further, the evaporation side and condensation sideheat pipes 3 a, 3 b, evaporation side and condensation side headers 5 a,5 b, and connecting parts 7 form a closed loop. Water, alcohol, oranother evaporable and condensable working fluid is sealed inside these.Due to this, the working fluid circulates through the evaporator 1 andcondenser 2.

Here, among the two connecting parts 7, the one arranged at the topside, connecting the first evaporation side header 51 a and firstcondensation side header 51 b, and guiding working fluid evaporated atthe evaporator 1 to the condenser 2 will be called the “evaporation sideconnecting part 71”. Further, among the two connecting parts 7, the onearranged at the bottom side, connecting the second evaporation sideheader 52 a and second condensation side header 52 b, and guiding theworking fluid condensed at the condenser 2 to the evaporator 1 will becalled the “condensation side connecting part 72”.

In the present embodiment, the second condensation side header 52 b isarranged so that it becomes higher than the second evaporation sideheader 52 a when the exhaust heat recovery device is mounted in avehicle in the horizontal state. Further, at the condensation sideconnecting part 72, the end at the condenser 2 side is connected to thesecond condensation side header 52 b, while the end at the evaporator 1side is connected to the heat pipe 30 a at the side closest to thecondenser 2 among the plurality of evaporation side heat pipes 3 a.

Further, the condensation side connecting part 72 is arranged tiltedwith respect to the horizontal direction so that the portion of the sidefar from the condenser 2 becomes lower than the portion of the sideclose to the condenser 2 when the exhaust heat recovery device ismounted in a vehicle in the horizontal state. That is, the condensationside connecting part 72 is tilted with respect to the horizontaldirection so as to become lower from the condenser 2 side toward theevaporator 1 side. In the present embodiment, the tilt angle θ of thecondensation side connecting part 72 with respect to the horizontaldirection is made 3° to 20° in range.

As explained above, by tilting the condensation side connecting part 72in advance so that the portion at the side far from the condenser 2becomes lower than the portion at the side close to the condenser 2,when the exhaust heat recovery device as a whole is tilted so that theevaporator 1 becomes higher than the condenser 2, the water headdifference between the evaporator 1 and the condenser 2 can be kept frombecoming smaller. Due to this, even when tilted, a sufficient amount ofworking fluid can be refluxed from the condenser 2 to the evaporator 1,so the heat exchange performance can be secured. Further, when theexhaust heat recovery device as a whole is tilted so that the evaporator1 becomes higher than the condenser 2, it is possible to prevent workingfluid from ending up remaining in the condensation side connecting part72. For this reason, blockage or breakage of the condensation sideconnecting part 72 under a low temperature environment can be prevented.

However, the tilt angle in the vehicle width direction of a road surfaceusually envisioned is not more than 20°. For this reason, by making thetilt angle θ of the condensation side connecting part 72 with respect tothe horizontal direction 3° to 20° in range, it is possible to deal withthe usually envisioned range of tilt of a road surface.

Other Embodiments

Note that in the above embodiments, the condenser 2 was configured witha plurality of condensation side heat pipes 3 b arranged in parallel sothat their longitudinal directions matched with the vertical direction,but the invention is not limited to this. The condenser 2 may beconfigured in any way.

Further, in the second embodiment, the first housing 100 was providedwith a condensed water catch 111, but this need not be provided.

Further, in the third and fourth embodiments, the evaporation side heatpipes 3 a were formed from pairs of shaped plates 31, 32 mating incross-section along the longitudinal direction, but the evaporation sideheat pipes 3 a need not be split.

While the invention has been described with reference to specificembodiments chosen for purpose of illustration, it should be apparentthat numerous modifications could be made thereto by those skilled inthe art without departing from the basic concept and scope of theinvention.

1. An exhaust heat recovery device carried in a vehicle using aninternal combustion engine as a drive source for operation and providedwith an evaporator arranged in an exhaust gas passage through whichexhaust gas exhausted from the internal combustion engine runs,exchanging heat between the exhaust gas and an evaporable andcondensable working fluid sealed inside it, and thereby evaporating theworking fluid and a condenser arranged in the cooling water passagethrough which cooling water of the internal combustion engine runs,exchanging heat between the working fluid evaporated by the evaporatorand cooling water, and thereby condensing the working fluid, wherein theevaporator and condenser are arranged in a closed loop channel throughwhich the working fluid circulates, the evaporator and condenser arearranged to adjoin each other in the substantially horizontal direction,the evaporator has a plurality of evaporation side heat pipes arrangedin parallel and is provided with a first communicating partcommunicating with first ends of the plurality of evaporation side heatpipes and a second communicating part communicating with the other ends,and, when mounted in a vehicle in the horizontal state, the secondcommunicating part arranged at the bottom among the two communicatingparts is positioned with the side far from the condenser lower than theside near it.
 2. An exhaust heat recovery device as set forth in claim1, further provided with: an evaporation side connecting part guidingsaid working fluid evaporated by said evaporator to said condenser and acondensation side connecting part guiding said working fluid condensedat said condenser to said evaporator, when mounted in a vehicle in thehorizontal state, said condensation side connecting part beingpositioned with the side far from said condenser lower than the sideclose to said condenser.
 3. An exhaust heat recovery device carried in avehicle using an internal combustion engine as a drive source foroperation and provided with an evaporator arranged in an exhaust gaspassage through which exhaust gas exhausted from the internal combustionengine runs, exchanging heat between the exhaust gas and an evaporableand condensable working fluid sealed inside it, and thereby evaporatingthe working fluid, a condenser arranged in the cooling water passagethrough which cooling water of the internal combustion engine runs,exchanging heat between the working fluid evaporated by the evaporatorand cooling water, and thereby condensing the working fluid, anevaporation side connecting part guiding said working fluid evaporatedat said evaporator to said condenser, and a condensation side connectingpart guiding said working fluid condensed at said condenser to saidevaporator, when mounted in a vehicle in the horizontal state, thecondensation side connecting part being positioned with the side farfrom said condenser below the side close to said condenser.
 4. Anexhaust heat recovery device as set forth in claim 1, wherein whenmounted in a vehicle in the horizontal state, the bottom ends of saidevaporation side heat pipes at the side far from said condenser amongthe plurality of evaporation side heat pipes are positioned lower thanthe bottom ends of said evaporation side heat pipes at the close side.5. An exhaust heat recovery device as set forth in claim 1, furtherprovided with a valve mechanism provided at a downstream side in saidcondenser and switching the channel through which the condensed workingfluid flows into said evaporator.